Analysis Of Fourier Transform Infrared Spectra Research Articles

Harnessing nature's potential: Alpinia galanga methanolic extract mediated green synthesis of silver nanoparticle, characterization and evaluation of anti-neoplastic activity.

With the advent of nanotechnology, the treatment of cancer is changing from a conventional to a nanoparticle-based approach. Thus, developing nanoparticles to treat cancer is an area of immense importance. We prepared silver nanoparticles (AgNPs) from methanolic extract of Alpinia galanga rhizome and characterized them by UV-Vis spectrophotometry, Fourier transform Infrared (FTIR) spectroscopy, Zetasizer, and Transmission electron Microscopy (TEM). UV-Vis spectrophotometry absorption spectrum showed surface plasmon between 400 and 480nm. FTIR spectrum analysis implies that various phytochemicals/secondary metabolites are involved in the reduction, caping, and stabilization of AgNPs. The Zetasier result suggests that the particles formed are small in size with a low polydispersity index (PDI), suggesting a narrow range of particle distribution. The TEM image suggests that the particles formed are mostly of spherical morphology with nearly 20-25nm. Further, the selected area electron diffraction (SAED) image showed five electron diffraction rings, suggesting the polycrystalline nature of the particles. The nanoparticles showed high anticancer efficacy against cervical cancer (SiHa) cell lines. The nanostructures showed dose-dependent inhibition with 40% killing observed at 6.25µg/mL dose. The study showed an eco-friendly and cost-effective approach to the synthesis of AgNPs and provided insight into the development of antioxidant and anticancer agents.

Novel LiFePO4/very-few-layer-graphene (LFP/VFLG) composites to improve structural and electrochemical properties of lithium-ion battery cathode

LiFePO4/Very-few-layer-graphene (LFP/VFLG) composites have been prepared using the sol-gel method for lithium-ion battery cathode. VFLG dominated by 1∼3 layers was obtained from an economical and environmentally benign process. Structural properties of LFP/VFLG composites were studied using Fourier-transform infrared spectra (FTIR) spectroscopy, X-ray diffractometry (XRD), high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy, while the electrochemical performance was measured using galvanostatic discharge, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) tests. The FTIR analysis confirmed that incorporating VFLG neither affected the chemical structure of LiFePO4 nor initiated any side reactions during the LiFePO4 formation reaction. The XRD results showed that LFP/VFLG composites had better lattice parameters, crystallinity, and phase purity than LiFePO4 without VFLG addition. The Raman spectroscopy analysis indicated that LFP/VFLG composites had a lower disorder in the carbon arrangement. HRTEM results indicated that a VFLG was successfully wrapped around the LFP particle offers a versatile way to enhanced electrochemical performance of LFP/VFLG composites. The galvanostatic discharge profiles showed an enhancing specific discharge capacity of up to 58.3% after incorporating VFLG. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests revealed that LFP/VFLG delivered small polarization, low inner resistance, high electrochemical reaction reversibility, and high lithium-ion diffusion coefficient. VFLG is a promising additive to improve the structural and electrochemical properties of the LiFePO4 cathode of lithium-ion batteries.

Adsorption of Ammonium, Nitrate, and Phosphate on Hydrochars and Biochars

Biochar (BC) and hydrochar (HC) have attracted considerable attention owing to their versatile characteristics and proven effectiveness in diverse technical fields. Solid BC is generated as a result of the dry carbonisation process of pyrolysis, in contrast to the slurry HC, which is produced during the hydrothermal carbonisation process. In this study, we evaluated the adsorption potential of two hydrochar samples (HCs) and three biochar samples (BCs) produced from sugar cane bagasse. The adsorption capacity of these samples was tested for ammonium, nitrate, and phosphate ions under various conditions. The BCs and HCs were subjected to characterisation using a CHNS/O analyser, the zeta potential, and Fourier transform infrared (FTIR). Elevating the pyrolysis temperature of the biochar resulted in changes in the fixed carbon and ash contents, while the volatile matter and H/C and O/C atomic ratios decreased. As the residence time increased, the H/C ratio and volatile matter content of the hydrochars (HCs) decreased. However, the fixed carbon content, ash content, and O/C and C/N ratios exhibited an increase. Thermodynamics, adsorption isotherms, and pH were also taken into consideration. The FTIR spectra analysis indicated that the carboxyl and ester functional groups present in both the BCs and HCs displayed reduced peak intensities subsequent to the adsorption of the three ions. While the adsorption was exothermic, we noticed that the adsorption capacity increased with temperature. The results indicate that sorption was homogenous across all binding sites, as evidenced by the optimal fit to the Langmuir isotherm. The research findings indicate that the adsorption capacity of various BC and HC adsorbents is significantly influenced by the surface area of the adsorbents in the case of nitrate and phosphate, but in the case of ammonia, adsorption is dictated by the functional polar groups present on the adsorbent surface.

Magnesium-Doped Nano-Hydroxyapatite/Polyvinyl Alcohol/Chitosan Composite Hydrogel: Preparation and Characterization.

Polyvinyl alcohol/Chitosan hydrogel is often employed as a carrier because it is non-toxic, biodegradable, and has a three-dimensional network structure. Meanwhile, Magnesium-doped nano-hydroxyapatite(Mg-nHA) demonstrated high characterization to promote the osteogenic differentiation of bone marrow derived mesenchymal stem cell(BMSCs). Therefore, in order to develop a porous hydrogel scaffold for the application of bone tissue engineering, an appropriate-type Mg-nHA hydrogel scaffold was developed and evaluated. A composite hydrogel containing magnesium-doped nano-hydroxyapatite (Mg-nHA/PVA/CS) was developed using a magnetic stirring-ion exchange method and cyclic freeze-thaw method design, with polyvinyl alcohol and chitosan as the main components. Fourier transform infrared spectra (FTIR), electron energy dispersive spectroscopy (EDS), X-ray photoelectron spectrometer (XPS) and scanning electron microscopy (SEM) were employed to analyze the chemical structure, porosity, and elemental composition of each hydrogels. The equilibrium swelling degree, moisture content, pH change, potential for biomineralization, biocompatibility, the osteogenic potential and magnesium ion release rate of the composite hydrogel were also evaluated. SEM analysis revealed a well-defined 3D spatial structure of micropores in the synthesised hydrogel. FTIR analysis showed that doping nanoparticles had little effect on the hydrogel's structure and both the 5% Mg-nHA/PVA/CS and 10% Mg-nHA/PVA/CS groups promoted amide bond formation. EDS observation indicated that the new material exhibited favourable biomineralization ability, with optimal performance seen in the 5% Mg-nHA/PVA/CS group. The composite hydrogel not only displayed favourable water content, enhanced biocompatibility, and porosity (similar to human cancellous bone), but also maintained an equilibrium swelling degree and released magnesium ions that created an alkaline environment around it. Additionally, it facilitated the proliferation of bone marrow mesenchymal stem cells and their osteogenic differentiation. The Mg-nHA/PVA/CS hydrogel demonstrates significant potential for application in the field of bone repair, making it an excellent composite material for bone tissue engineering.

Mimicking Natural Antioxidant Systems for Improved Photostability in Wide-Band-Gap Perovskite Solar Cells.

Fostered by the top power conversion efficiencies (PCEs) of lab-scale devices, industrialization of perovskite solar cells is underway. Nevertheless, the intrinsically poor stability of these materials still represents a major concern. Herein, inspired by Nature, the use of β-carotene in perovskite solar cells is proposed to mimic its role as a protective pigment, as occurs in natural photosynthesis. Laser-mediated photostability (LMPS) assessment, Fourier-transform infrared spectra analysis acquired in attenuate total reflectance (ATR-FTIR), spectroscopy ellipsometry (SE), and time-resolved photoluminescence (TRPL) measurements under stress conditions prove that the inclusion of a thin β-carotene interlayer promotes a high improvement in the photostability of the perovskite films against photooxidation. Importantly, this is accompanied by an improvement of the solar cell PCE that approaches 20% efficiency with no hysteresis, which is among the highest values reported for a mixed halide (I-Br) perovskite with a band gap of 1.74 eV, relevant for coupling with silicon in tandem cells.

Biogenic synthesis of silver nanoparticles using essential oil of aerial part of cyclospermum leptophyllum and their application in colorimetric determination of metallic ions

The focus of this research was to synthesize biogenic silver nanoparticles (AgNPs) using the essential oil of the aerial part of Cyclospermum leptophyllum (CLEO) and investigate their colorimetric determination of metallic ions. In the synthesis of CLEO mediated AgNPs (CLEO-AgNPs), the one-factor-at-a-time method was used to optimize the reaction parameters. Ultraviolet-visible (UV-Vis) peak of CLEO-AgNPs was determined at 426 nm. Fourier transform-infrared (FTIR) spectra analysis identified the functional groups participating in the bio-reducing, capping, and stabilizing processes in the CLEO-AgNPs synthesis. Scanning electron microscope (SEM) image demonstrated the predominately spherical shape and the average size of 70.86+1.80 nm of CLEO-AgNPs. Energy dispersive X-ray spectroscopy (EDX) peak profile depicted the presence of Ag elements in CLEO-AgNPs. The X-ray diffraction (XRD) peaks observed at 38.5°, 44°, 65°, and 77° which represent Ag(111), Ag(200), Ag(220), and Ag(311) lattice faces, respectively. The average zeta nanosize, zeta potential, and polydispersity index of CLEO-AgNPs were determined as 69.70 nm, -43.5 mV, and 0.256, respectively. The stability test exhibited the prolonged storage stability of CLEO-AgNPs for over six months at room temperature. CLEO-AgNPs demonstrated the potential colorimetric detection of K+, Mg2+, Al3+, Cr6+, Mn2+, Fe3+, Ni2+, Cu2+, Zn2+, Hg2+, Pb2+, and Cd2+ ions in the real samples.
 KEY WORDS: Cyclospermum leptophyllum, Essential oil, Biogenic silver nanoparticles, Bio-reductants, Colorimetric detection 
 Bull. Chem. Soc. Ethiop. 2024, 38(1), 213-228. DOI: https://dx.doi.org/10.4314/bcse.v38i1.16

Investigations on growth, XRD, strain, FTIR, UV–Vis NIR, photoluminescence, SHG, and Z-scan analyses of L-cysteine picrate single crystal for NLO and optical limiting applications

Organic single crystal of L-cysteine picrate (LCP), an efficient NLO material for frequency conversion, optoelectronic, and optical limiting applications has been grown within 20 days by Slow Evaporation Solution Technique (SEST). PXRD analysis shows that the LCP is subjected to the noncentrosymmetric space group of P21 with a monoclinic crystal system. The very low strain value depicts that the level and dislocations of the defect in the lattice of LCP crystal are very low. The various functional group assignments were investigated by using Fourier-Transform Infrared (FTIR) spectrum analysis with the range of 4000–400 cm−1. The optical analysis (UV–Visible) confirmed that the crystal has a lower cut-off wavelength of 250 nm and very low absorption in the entire visible region. Photoluminescence (PL) spectrum analysis confirmed that the material exhibits blue emission and is suitable for LED device fabrication. The SHG efficiency for LCP crystal is established to be 1.7 times higher than KDP material. Z-scan measurement determined the LCP exhibits two-photon absorption-induced optical limiting action with a nonlinear absorption coefficient of 0.70 × 10−10 m/W and onset limiting threshold of 2.36 × 1012 W/m2 which indicates that it can be used in making laser protection gadgets.

Structure, thermal and crystallization behavior of lead-bismuth silicate glasses

Lead-bismuth silicate glasses were synthesized using a standard melt-quenching technique, varying the compositions within the range of (80-x-y)PbO–(10+x)Bi2O3–(10+y)SiO2, where x and y were between 0 and 20 wt%. The glasses were subjected to comprehensive analysis, including X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and dilatometry, to investigate their crystallization behavior, thermal properties, and structure. The obtained glass samples were confirmed to be amorphous through X-ray diffraction and scanning electron microscopy. Fourier-transform infrared spectra analysis indicated that the glasses consisted mainly of PbO4, BiO6, and SiO4 structural units. Differential thermal analysis curves were used to estimate the glass transition, crystallization, and melting temperatures, and the results showed increased thermal stability and decreased crystallization tendency with increasing SiO2 content in the glass. X-ray diffraction analysis was utilized to identify the specific crystalline phases that were formed after the glass was subjected to heat treatment. Dilatometric measurements demonstrated that the investigated glasses possess a wide range of coefficient of thermal expansion values (6.8–11.1 ppm/°C), a low glass transition temperature (335–475°С), and a low dilatometric softening temperature (355–505°С). These results have significant implications for developing oxide glasses with specific thermal characteristics suitable for a wide range of applications.

Insights into the mechanisms of L. salivarius CECT5713 resistance to freeze-dried storage

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits. However, it is sensitive to freeze-drying and storage in the dried state, thus limiting its commercial exploitation. Our objective was to identify markers of cell resistance by applying multiscale characterization to L. salivarius CECT5713 cell populations exhibiting different resistance to freeze-dried storage. Cells were produced under two different sets of production conditions differing in the culture parameters (temperature, neutralizing solution, and harvesting time) and the protective formulation composition. The culturability, membrane integrity, and cell biochemical composition assessed by Fourier transform infrared (FTIR) micro-spectroscopy were evaluated after freezing, freeze-drying, and subsequent storage at 37 °C. Membrane properties (fatty acid composition, membrane fluidity, and phospholipid organization), as well as matrix physical properties (glass transition temperature and water activity), were determined. The most resistant cells to freeze-dried storage exhibited the highest cyclic fatty acid content and the most rigid membrane. Freeze-drying and storage induced damage to membrane integrity, proteins, nucleic acids, and constituents of the peptidoglycan cell wall. From the FTIR spectra analysis, we propose the minimization of the variations of the 1058 and 1714 cm−1 vibration bands (that arise mainly from symmetric C–O–C stretching and CO stretching, respectively) induced by the freeze-drying process as a marker of storage stability. We confirmed that a matrix with a glass transition temperature at least 50 °C higher than the storage temperature is crucial for L. salivarius CECT5713 storage stability. In addition, this work explored promising FTIR methods for a better understanding of the protection mechanisms involved.

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy for Forensic Screening of Long-Term Alcohol Consumption from Human Nails.

Fourier transform infrared (FT-IR) spectroscopy is used throughout forensic laboratories for many applications. FT-IR spectroscopy can be useful with ATR accessories in forensic analysis for several reasons. It provides excellent data quality combined with high reproducibility, with minimal user-induced variations and no sample preparation. Spectra from heterogeneous biological systems, including the integumentary system, can be associated with hundreds or thousands of biomolecules. The nail matrix of keratin possesses a complicated structure with captured circulating metabolites whose presence may vary in space and time depending on context and history. We developed a new approach by using machine-learning (ML) tools to leverage the potential and enhance the selectivity of the instrument, create classification models, and provide invaluable information saved in human nails with statistical confidence. Here, we report chemometric analysis of ATR FT-IR spectra for the classification and prediction of long-term alcohol consumption from nail clippings in 63 donors. A partial least squares discriminant analysis (PLS-DA) was used to create a classification model that was validated against an independent data set which resulted in 91% correctly classified spectra. However, when considering the prediction results at the donor level, 100% accuracy was achieved, and all donors were correctly classified. To the best of our knowledge, this proof-of-concept study demonstrates for the first time the ability of ATR FT-IR spectroscopy to discriminate donors who do not drink alcohol from those who drink alcohol on a regular basis.

Chemometrics Approach Based on Wavelet Transforms for the Estimation of Monomer Concentrations from FTIR Spectra.

Fourier-transform infrared (FTIR) spectroscopy can detect the presence of functional groups and molecules directly from a mixed solution of organic molecules. Although it is quite useful to monitor chemical reactions, quantitative analysis of FTIR spectra becomes difficult when various peaks of different widths overlap. To overcome this difficulty, we propose a chemometrics approach to accurately predict the concentration of components in chemical reactions, yet interpretable by humans. The proposed method first decomposes a spectrum into peaks with various widths by the wavelet transform. Subsequently, a sparse linear regression model is built using the wavelet coefficients. Models by the method are interpretable using the regression coefficients shown on Gaussian distributions with various widths. The interpretation is expected to reveal the relation of broad regions in spectra to the model prediction. In this study, we conducted the prediction of monomer concentration in copolymerization reactions of five monomers against methyl methacrylate by various chemometric approaches including conventional methods. A rigorous validation scheme revealed that the proposed method overall showed better predictive ability than various linear and non-linear regression methods. The visualization results were consistent with the interpretation obtained by another chemometric approach and qualitative evaluation. The proposed method is found to be useful for calculating the concentrations of monomers in copolymerization reactions and for the interpretation of spectra.

Facile synthesis of fluorinated graphene for surface self-assembly of aluminum hydride

A facile method, refluxing with hydrothermal process, was used to synthesize the fluorinated graphene sheets (FGS) with high F/C ratio. Then, the surface of aluminum hydride (AlH3) was coated with FGS by means of liquid self-assembly process. The structure and performance of FGS were characterized through fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM) and elemental analyzer. FTIR spectra show that the FGS have obvious absorption peak of CF bond. Raman spectra display many defects on FGS. XPS spectra and elemental analysis also prove the existence of CF bond, and the content of fluorine is more than 25%. From SEM photos we can see that FGS have thin layers with some curled wrinkles. TEM photos demonstrate intuitively the FGS has a few layers. At last, the aluminum hydride (AlH3) was coated with FGS by means of liquid self-assembly process, and AlH3 samples before and after treated were characterized through hydrogen content (H%) analysis, X-ray diffraction (XRD), FTIR, SEM and differential thermal analysis (DTA), ect. The results demonstrate that there is only a little FGS on the surface of AlH3, which won't affect the effective H% and release efficiency of hydrogen. AlH3@FGS also reduces the mechanical sensitivity of solid propellant with AlH3, which will remarkably promote the application of AlH3 in the novel high-energy solid propellant.

Effect of NaOH-catalyzed organosolv pretreatment on the co-production of ethanol and xylose from poplar

NaOH-catalyzed organosolv pretreatment was proposed to degrade lignin, retain cellulose and hemicellulose in poplar, and the pretreated substrates was used to produce ethanol and xylose simultaneously. After the organosolv pretreatment conducted at 205 ºC for 20 min with 1.2% NaOH, the optimal ethanol concentration and xylose yield reached 30.1 g/L and 10.3 g/100 g raw material after 48 h, respectively, and the xylose yield was positively correlated with the ethanol concentration (R2 =0.934). The alteration in chemical composition and structure enhanced the ethanol concentration and xylose yield, which was revealed by Scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectrum (FT-IR), Thermogravimetric (TG), and correlation analysis. In addition, their capacity for generating ethanol and xylose during three fermentation processes was comprehensively compared. The results indicated that SSF was beneficial to improve ethanol concentration, and SHF was in favour of enhancing xylose and ethanol yields to 95.4% and 85.3% based on retained xylan after pretreatment and the fermentable glucose, respectively. The NaOH enhanced organosolv pretreatment exhibited excellent performance in converting poplar into energy and chemicals, which presented a new idea for biomass refining.

Biosynthesis of Silver Nanoparticles and Exploring Their Potential of Reducing the Contamination of the In Vitro Culture Media and Inducing the Callus Growth of Rumex nervosus Explants.

Among biological methods, green synthesis of the nanomaterials using plant extracts was shown to be an environmentally friendly, economical, and simple approach. In the current study, the biogenic synthesis of silver nanoparticles (AgNPs) was achieved using the leaf extract of Hibiscus tiliaceus, in order to prevent the contamination of the tissue culture media and induce callus growth. The nanostructures of the fabricated AgNPs were characterized using UV-visible spectroscopy, Fourier transform infra-red spectra (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), zeta size, and zeta potential techniques. Our results indicate that The UV-vis spectrum of AgNPs exhibited an absorption band at 415 nm. The FTIR analysis identified the functional groups which could involve in the reduction of silver ions to AgNPs, this was also confirmed by the (hkl) diffraction peaks in the XRD diffractogram. Moreover, the TEM analysis showed a spherical nanoparticle with a size ranging from 21 and 26 nm. Thereafter, the potential antibacterial and antifungal activity of the biogenic AgNPs was evaluated against Bacillus pumilus and Alternaria alternata which were isolated from the in vitro culture media and identified based on 16S rDNA and ITS rDNA sequences, respectively. The results showed that the AgNPs significantly inhibited the growth of Alternaria alternata and Bacillus pumilus at all applied concentrations (5, 10, 20 and 40 mg/L). Compared to the control more fungal radial growth reduction (42.59%,) and bacterial inhibition (98.12%) were registered in the plates containing high doses of AgNPs (40 mg/L). Using Rumex nervosus explants, the biosynthesized AgNPs were tested for their impact to promote callus growth. The obtained results showed a significant effect of AgNPs on callus fresh weight at all applied doses. Moreover, AgNPs treatments showed a polymorphism of 12.5% which was detected by RAPD markers. In summary, the results revealed that AgNPs (40 mg/L) can be effectively added to the in vitro culture media for reducing microbial contamination and improving callus growth while greatly maintaining its genetic stability.

Identification of Tree Species and Extent of Material Deterioration of Wood Components in the Yangjia Courtyard Ancient Building

AbstractThe identification of the tree species and the extent of material deterioration in the wooden components of the walkway of the first courtyard of the ancient Yangjia Courtyard were analyzed in this study using bright-field microscopy, polarized light, fluorescence, and Fourier-transform infrared (FTIR) spectroscopy methods. The results are as follows: (1) samples No. 1 and No. 2, and No. 4, No. 3, and No. 5 taken from the roots of the wooden pillars were identified as lace-bark pine wood (Pinus bungeana), poplar woods (Populus spp.), large-fruited elm wood (Ulmus macrocarpa), and spruce wood (Picea sp.), respectively on the basis of observation of anatomical structural characteristics and analysis of selection principle of “local selection” in ancient buildings. (2) The observation of polarization and fluorescence and the analysis of FTIR spectra showed that the brightness of crystalline cellulose birefringence reduced severely, and analysis of FTIR spectra showed that the absorption peaks representing cellulose and hemicellulose in the lace-bark pine and spruce wooden components disappeared or decreased. However, the polarization and fluorescence and the FTIR spectra of the poplar and elm wooden components showed that the brightness of the crystalline cellulose birefringence and the absorption peaks remained constant, as the controls did. (3) According to the results of the effects of the polarization and fluorescence effects and the FTIR spectra, we concluded that the lace-bark pine and spruce wooden components were severely attacked by brown rot fungi; in contrast, the wooden components of poplar and elm were not attacked by wood decay fungus, but were attacked by insects. These results provide scientific guidance for subsequent preventive conservation such as preservative treatment and insect prevention.

Impaired Extracellular Proteostasis in Patients with Heart Failure

Proteostasis impairment and the consequent increase of amyloid burden in the myocardium have been associated with heart failure (HF) development and poor prognosis. A better knowledge of the protein aggregation process in biofluids could assist the development and monitoring of tailored interventions. To compare the proteostasis status and protein's secondary structures in plasma samples of patients with HF with preserved ejection fraction (HFpEF), patients with HF with reduced ejection fraction (HFrEF), and age-matched individuals. A total of 42 participants were enrolled in 3 groups: 14 patients with HFpEF, 14 patients with HFrEF, and 14 age-matched individuals. Proteostasis-related markers were analyzed by immunoblotting techniques. Fourier Transform Infrared (FTIR) Spectroscopy in Attenuated Total Reflectance (ATR) was applied to assess changes in the protein's conformational profile. Patients with HFrEF showed an elevated concentration of oligomeric proteic species and reduced clusterin levels. ATR-FTIR spectroscopy coupled with multivariate analysis allowed the discrimination of HF patients from age-matched individuals in the protein amide I absorption region (1700-1600 cm-1), reflecting changes in protein conformation, with a sensitivity of 73 and a specificity of 81%. Further analysis of FTIR spectra showed significantly reduced random coils levels in both HF phenotypes. Also, compared to the age-matched group, the levels of structures related to fibril formation were significantly increased in patients with HFrEF, whereas the β-turns were significantly increased in patients with HFpEF. Both HF phenotypes showed a compromised extracellular proteostasis and different protein conformational changes, suggesting a less efficient protein quality control system.

Feasibility Assessment of the Identification of the Source of Condensed Tannins in Leathers by FTIR Spectroscopy and Chemometrics

This study aimed to investigate the feasibility of identifying the type of plant used in the tanning of leathers by cost-effective Fourier transform infrared (FTIR) spectroscopy. The investigation was performed on European horse-chestnut (fruit peel), mimosa, and quebracho and three specimens of mimosa-tanned leathers. Tannin extraction from plants was performed in an ultrasonic bath using acetone-water solvent (70%). Tannin extraction from leathers was carried out from the corium fibers using acetone-water solvent (1:1). After extraction, filtration, centrifugation, and solvent removal, the samples were subjected to FTIR spectroscopy. Principal Component Analysis (PCA) and hierarchical clustering were used to identify the source of tannins based on FTIR results. In addition to FTIR spectra, their first and second derivatives were also used in statistical analyses. The obtained FTIR spectra and their derivatives and the results of PCA and hierarchical clustering showed that rich plant sources of condensed tannins can be well differentiated by spectroscopy in the fingerprint region (700-1800cm-1). The PC1-PC2 plot in the analysis of FTIR spectra and the PC2-PC3 plot in the analysis of derivatives showed the best ability to differentiate and identify the extracts. Multivariate PCA and cluster analyses performed well in identifying the type of plant used in the tanning of the studied leathers, especially when applied to the derivatives of FTIR spectra.

Surface chemistry of xanthan gum interactions with bastnaesite and fluorite during flotation

Rare earth (RE) minerals are resources crucial to mining strategies. In particular, bastnaesite is a major mineral from which rare earth elements (REEs), especially light rare earth elements (LREEs), can be extracted. However, the separation of bastnaesite and fluorite via flotation is challenging owing to their similar physical and chemical properties. In this study, xanthan gum (XG) was evaluated as a novel depressant of bastnaesite and fluorite in an octyl hydroxamic acid (OHA) system. The flotation behavior and surface chemistry by which the XG interacted with the bastnaesite and fluorite were investigated via analyses of micro-flotation tests, adsorption density measurements, zeta potentials, Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectra (XPS). The micro-flotation results showed that the XG was an efficient selective depressant for the fluorite but had minimal impact on the bastnaesite. The results of the adsorption density and zeta potential analyses indicated that the adsorption of the XG occurred on both the bastnaesite and fluorite surfaces. They also indicated that the XG hindered the subsequent adsorption of the OHA on the surface of the fluorite, but the OHA was able to attach to the surface of the bastnaesite. The results of the FTIR and XPS analyses revealed that in the interaction between the XG and fluorite, chemical and hydrogen bonding adsorption occurred via complexation between the –COO- and –OH groups within the XG and the Ca or F sites on the surface of the fluorite, whereas only hydrogen bonding and electrostatic attraction occurred between the XG and bastnaesite surface. These results provide a more robust theoretical basis and sound guidance for the selection of effective depressants in the flotation separation of bastnaesite and fluorite.

Performance testing of modified waterborne polyurethane coating applied on laminated bamboo

The effects of different UV absorbents and preservatives on the weatherability of modified waterborne polyurethane (WPU) printed laminated bamboo were investigated. Three types of UV absorbents including 2-hydroxy-4-n-octoxy-benzophenone (UV-531), 2-(2 H-benzotriazol-2-yl)-4-(1,1,3,3 tetramethylbutyl) phenol (UV-329), and nano-TiO2, and four types of preservatives including boric acid (BA), borax (BX), ammonium polyphosphate (APP), and disodium octaborate tetrahydrate (DOT) were selected to modify WPU coatings. The printed laminated bamboo was tested to evaluate the coating physical and chemical properties and dimensional stability. Thirteen coating types were tested. The results showed that the 0 (20% WPU), 5 (UV-531-BA/BX), 6 (UV-531-BA/BX/APP), 7 (UV-531-BA/BX/DOT), 8 (UV-531-BA/BX/APP/DOT), and 9 (nano-TiO2/BA/BX) samples performed well in adhesion, abrasion resistance, hardness, and temperature denaturation. Fourier transform infrared (FT-IR) spectra analyses and dimensional stability analysis were carried out on the six kinds of coatings screened out. FT-IR spectra analyses showed the successful introduction of UV light absorbers and flame retardants, whereas test results of hygroscopicity showed that the coated test material improved the dimensional stability performance. Test material 8(UV-531-BA/BX/APP/DOT) had the best dimensional stability performance.

Analysis of FTIR Spectra, Flavonoid Content and Anti-Tyrosinase Activity of Extracts and Lotion from Garcinia schomburgkiana by Multivariate Method

In this study, fourier transform infrared (FTIR) study, total flavonoid content and anti-tyrosinase activity of leaf, seed and flesh extracts of Garcinia schomburgkiana and lotion formulation from the extracts were carried out. Additionally, a relationship among FTIR spectra, total flavonoid content and anti-tyrosinase activity was analysed by partial least squares structural equation modelling (PLS-SEM) and principal component analysis (PCA) analysis. The result indicated that the highest total flavonoid content was found in leaf ethanol extract (214.00 ± 7.32 mg rutin equivalent per mg extract). For lotion samples, lotion containing leaf ethanol extract revealed the strongest level of total flavonoid content (5.51 ± 0.04 mg rutin equivalent per mL lotion). Moreover, anti-tyrosinase activity was observed in lotion containing the extracts (1/EC50 ranged from 0.0063 to 7.2334) higher than that of aqueous, ethanol and propanediol extracts (1/EC50 ranged from 0.0099 to 0.5319). The FTIR result confirmed the presence of various function groups in different parts of G. schomburgkiana and lotion samples, which involved the structure of flavonoids namely O-H stretch, C=O bending vibrations, unsaturation bonds, phenol or tertiary alcohol (O-H bend), C-O-H deformation and C-O stretching vibrations of aromatic ethers. The PLS-SEM analysis indicated a moderate positive relationship between the total flavonoid content and FTIR data, significantly (β = 0.502, t = 2.239, p-value < 0.05). The FTIR and subsequent PCA analysis could differentiate of aqueous, ethanol and propanediol extracts and lotion samples.
 HIGHLIGHTS
 
 FTIR data positively correlated with total flavonoid content
 Extract and lotion samples revealed total flavonoid content and anti-tyrosinase activity
 The PLS-SEM analysis showed significantly positive relationship between the total flavonoid content and FTIR data
 FTIR and subsequent PCA analysis differentiated extracts and lotions
 
 GRAPHICAL ABSTRACT